slick66stang

I have a 02 gt stock and my rpms r at 500 at idle is this low or normal

99GTvert

500 seems low.

Mine at a cold start is about 1100-1200ish IIRC (haven't driven it in a long time). Normal temperature is not much lower.

Seabee1993

My 2000 GT is about 750-ish, and about the same as ^ he said about cold start.

barqsdrinker

My 2001 GT is about 1200-ish when cold and about 750 when warm. If it is in "D"rive (its an automatic) with my foot on the brake, it drops to about 600 or so.

cliffyk

It is low, most '02+ GTs are set in the tune to idle at 736 rpm in neutral though this is not a fixed value across the board--here are some values I observed in various tunes:

• 680 in CRAJ0.AOL3;
• 625 in FMAG0.RMR0;
• 736 in FBFG2.RKN2;
• 680 in RYAF1.MDE3;
• 736 in RYAF1.XSH2;
• 640 in RYBE2.YDH1;
• 720 in RVAFA.NUX2;
• 640 in RZAO1,BMD0;
• 705 in RVAF1.KSG0;

For automatic transmissions idle speed in Drive is usually set to be around 560 to 600.

99.44% of the time problems such as you describe are a failing/failed Idle Air Control (IAC) valve.

Here is how it can be tested:

• With the engine warm and idling disconnect the IAC electrical connector, the engine rpm should drop significantly or even stall--if it doesn't the IAC is bad buy a new one -or- it could be that the throttle stop screw is not properly set, click here to see how to do this;
  
  
• You can check the IAC with a multi-meter, unplug the electrical connector and measure the resistance between the two terminals, it should be 6 to 13 Ω--if it isn't the IAC is bad, buy a new one;
  
  
• Next check the resistance between each terminal and the IAC body, in both cases it should be better than 10 kΩ--if it is less the IAC is bad, buy a new one;

You can also check the voltage between the red wire at the IAC (connector plugged in, key on engine off (KOEO) and ground (the IAC body will work), it should be 12.0 V or more--if not you have a wiring problem...

Ford says it is not adjustable and cannot be cleaned:



That has been my experience, cleaning it may help but it is at best a temporary fix. You should be able to get a new IAC at any FLAPS for $90 or less.

If the IAC tests out OK then check the throttle stop screw preset (here's how), with age the adjusting screw tip and bellcrank tab will wear a bit and allow the throttle plate to close up a bit...

Dragonus18

+1

I just went through the same exact thing and that was the problem. it's an easy switch but if you have and kind of F/I than you have to use the motorcraft original part or your RPM's will potentially surge.